Like other prescription medicines, enzalutamide can cause side effects. Not every patient experiences the same reactions, and the severity can vary.
Patients should tell their healthcare professional about new or worsening symptoms, especially if symptoms interfere with normal activities.
Commonly Reported Effects
Reported adverse reactions associated with enzalutamide treatment can include:
- Fatigue
- Hot flushes
- Headache
- Dizziness
- High blood pressure
- Falls
- Fractures
- Reduced appetite
- Weight-related changes
- Nausea
- Musculoskeletal symptoms
The precise frequency and severity depend on the clinical setting and should be checked against the current product information.
Fatigue
Fatigue is an important treatment-related complaint.
Patients may experience:
- Reduced energy
- Increased need for rest
- Difficulty maintaining usual activities
- Reduced exercise tolerance
Practical measures such as maintaining appropriate activity, hydration, nutrition, and sleep routines may help some patients, but persistent or severe fatigue should be discussed with the healthcare team.
Hot Flushes
Hormonal treatment for prostate cancer can cause hot flushes.
Patients may notice:
- Sudden warmth
- Sweating
- Facial flushing
- Night-time discomfort
The healthcare team can discuss strategies for managing persistent symptoms.
Dizziness
Dizziness may increase the risk of falls.
Patients who experience dizziness should stand up slowly and take care around stairs, uneven surfaces, and other fall hazards.
If dizziness is severe, persistent, or associated with neurological symptoms, medical advice is appropriate.
High Blood Pressure
Blood pressure elevation can occur during treatment.
Patients with hypertension may require monitoring and, where appropriate, adjustment of their existing blood-pressure management.
Falls and Fractures
Falls are particularly important in older adults and people with reduced bone density.
Patients should tell their healthcare provider about:
- Repeated falls
- New difficulty walking
- Severe bone or joint pain
- Suspected fractures
Serious Side Effects
Some adverse reactions require urgent assessment.
Seizure
A seizure is a serious event and requires prompt medical attention.
Patients with a seizure history should discuss their risk before starting treatment.
Chest Pain or Cardiovascular Symptoms
Chest pain, pressure, severe shortness of breath, or other symptoms suggestive of a cardiac event require urgent evaluation.
Ischemic heart disease is an identified safety concern with enzalutamide.
Severe Allergic Reaction
Seek urgent help for:
- Difficulty breathing
- Swelling of the face or throat
- Severe rapidly developing rash
- Severe allergic symptoms
Severe Neurological Symptoms
Sudden confusion, severe headache, seizure, or visual disturbance should be evaluated urgently because these may indicate a serious neurological condition.
When to Contact the Doctor
Contact the healthcare team if side effects are:
- Persistent
- Getting worse
- Affecting daily activities
- Causing difficulty eating or drinking
- Increasing fall risk
- Associated with unusual bleeding or bruising
- Associated with new neurological symptoms
Managing Side Effects
Management depends on the specific reaction.
A doctor may recommend:
- Observation
- Supportive treatment
- Additional tests
- Temporary treatment interruption
- Dose adjustment
- Switching or changing another medicine
- Further specialist assessment
Patients should not make these decisions independently.
Side Effects and Treatment Response
The presence or absence of side effects does not reliably indicate whether enzalutamide is working.
Likewise, having no side effects does not mean the medicine is ineffective.
Cancer response should be assessed using appropriate clinical assessments, laboratory results, imaging, PSA trends where clinically relevant, and other measures selected by the treating team.
Reporting Adverse Reactions
Patients should report suspected adverse reactions to their doctor or pharmacist.
Healthcare professionals can determine whether a symptom may be related to enzalutamide, another medicine, the underlying cancer, or another medical condition.
Important Reminder
The official product information should be consulted for the complete list of adverse reactions and their reported frequencies.
The EMA identifies fatigue and several other reactions among adverse effects associated with enzalutamide and highlights seizure and ischemic heart disease as important safety considerations.